Notices
996 Forum
Sponsored by:
Sponsored by: LN Engineering

Engine Rebuild Part 3 (the finale)

 
Old 03-31-2012, 11:03 AM
  #181  
jrgordonsenior
Addict
Rennlist Member
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,294
Likes: 0
Received 0 Likes on 0 Posts
Default

FWIW I think you're choked up. The stock mufflers are extremely heavy and congested. An after market system, perhaps Fabspeed's, would expand your new motor's ability to breathe. Stay with the stock air box but switch to a better element, I use BMC.

4th gear is where most stock geared Porsches dyno. Mine have always been in 4th....

Here's my latest dyno sheet on a Dyno Dynamics machine. They produce considerably lower results than a Dynojet, many say 10% less. I'll have to get on a Dynojet if I want to race with NASA this year. I'll probably go to a 2.5 TB and hopefully get the WHP down to 270 or so.

Our motors are significantly different, you use the larger Nikies cylinders to get to 3.6, I used the 3.6 crank and rods with decked 3.4 heads, cams, and a 5 angle valve grind. I also have 3.8 manifolds to straight pipes, FVD's slightly enlarged throttle body, and GIAC's street flash. YMMV....




Uploaded with ImageShack.us
jrgordonsenior is offline  
Old 03-31-2012, 12:44 PM
  #182  
logray
User
Thread Starter
 
logray's Avatar
 
Join Date: May 2010
Location: Nor Cal
Posts: 1,851
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by ltusler View Post
...Is your TB the cable operated one? Measure the ID of it and if its smaller than 74mm. I have a spare 74mm you can try out...
Thanks for the offer! I remember looking at FVD's 76.4mm body years ago when I did my Softronic flash. Unfortunately, right around the time I bought the flash, Scott stopped supporting Motronic 5.2.2. Took my money and ran with it!

My T/B is stock cable op at 74.8 mm. Are you sure yours isn't 76.4mm? I don't remember a 74mm for the 996 (1998-2001), except maybe on a smaller Boxster engine. I'll send you a PM.

I would be open to throwing it on and taking it to the dyno again, which I'm starting to get the itch a little to see what was up with those torque figures.

I'm just not sure how much it could help without complimentary intake and exhaust porting. Heh maybe I could get out the dremel like speed rII did.

Originally Posted by speed rII View Post
To my knowledge, cars should be dynoed on the gear that is closest to 1 ratio. On 996 it's 5th gear... I bet that you would gain some hp if you dyno the car again with 5th gear. Wheelspeed is high, about 240km/h. If the dyno allows thesekind of speed's I would do new pull's
Interesting, even hte dyno operator Kevin noted it should be done at gear closest to 1:1 ratio. After looking at WSM, 4th gear is 1.22 and 5th is 1.02. The machine I used goes to 180mph which is about 150mph. It might take some convincing though, to get this machine spinning that fast.

Originally Posted by speed rII View Post
Was the dyno inertia or brake dyno? I believe that inertiadyno will show lower torgue figures allso, if dynoed in too small gear
It was an intertia dyno. A dynojet 424 linx, link below. As for higher numbers, I would want to see whatever is comparative, but it would also be interesting to see what it could do in 5th gear.

http://www.dynojet.com/automotive_dy...o/default.aspx

Originally Posted by jrgordonsenior View Post
FWIW I think you're choked up. The stock mufflers are extremely heavy and congested. An after market system, perhaps Fabspeed's, would expand your new motor's ability to breathe. Stay with the stock air box but switch to a better element, I use BMC.
I concurr... I'm guessing a lot of the problem with mine is on the intake side, with the stock box and stock filter, 3.4L T/B, and 3.4L porting. In fact the long term fuel trims have gone a little negative with the 3.6L injectors, which might indicate the same thing, less air means less fuel right! And that AFR graph might also indicate boring-ness happening inside. You're talking to someone that used to have EvoX CAI, IPD plenum, fabspeed headers, cats, and mufflers. I also have a K&N for the stock box I removed long ago while troubleshooting my MAF. But I think I'll throw it back in just for fun. I could have the fisterD mod done on my 3.6L stock muffers, at least shipping would be cheap since he's close to me. I think I would stop at fisterD though.

Originally Posted by jrgordonsenior View Post
Our motors are significantly different, you use the larger Nikies cylinders to get to 3.6, I used the 3.6 crank and rods with decked 3.4 heads, cams, and a 5 angle valve grind. I also have 3.8 manifolds to straight pipes, FVD's slightly enlarged throttle body, and GIAC's street flash. YMMV....
I'm contemplating reflashing my DME with the softronic flash, but without any support or much info from Scott on what he "tuned" I'm a little hesitant, don't want to do any damage. The first time I bricked my DME I had to learn how to flash it on the bench, now I've flashed 3 times on 2 different DMEs without issue (both PST2 and Softronic). The 5.2.2 is difficult to flash and some of the original models had bad NVRAM.

No doubt your other mods are exploiting your upgrades, the straight pipes and the throttle body. My valves also had a grind FWIW...
logray is offline  
Old 03-31-2012, 01:35 PM
  #183  
logray
User
Thread Starter
 
logray's Avatar
 
Join Date: May 2010
Location: Nor Cal
Posts: 1,851
Likes: 0
Received 1 Like on 1 Post
Default

I nearly forgot about plugs too... geez the snowball certainly gets bigger once it starts rolling down hill.

Last edited by logray; 03-31-2012 at 02:31 PM.
logray is offline  
Old 04-01-2012, 04:30 PM
  #184  
ltusler
Addict
Rennlist Member
 
ltusler's Avatar
 
Join Date: Jul 2005
Posts: 1,089
Likes: 0
Received 0 Likes on 0 Posts
Default

You're right I just measured it and it's 76mm. I think FVD opens them to 78mm? Not much thickness in the wall.
ltusler is online now  
Old 04-01-2012, 06:01 PM
  #185  
logray
User
Thread Starter
 
logray's Avatar
 
Join Date: May 2010
Location: Nor Cal
Posts: 1,851
Likes: 0
Received 1 Like on 1 Post
Default

PM sent on the larger T/B. Yes FVD goes to 76.4mm.

I tried looking for the 3.6L throttle body specs but couldn't find them.

For sure I think this might help, if the stock 3.4L head ports can handle the extra volume. Considering I've got the 3.6L mufflers and aftermarket headers, I am thinking this would help including the K&N w/ the stock air box.

I don't want to go crazy with mods nor tear into the engine again at this point, but I wouldn't mind giving this a go and maybe putting her back on the dyno to see if it can breathe easier.

Anyone out there know off the top what the 3.6L T/B measures out at (or would like to measure)?
logray is offline  
Old 04-02-2012, 11:53 AM
  #186  
jrgordonsenior
Addict
Rennlist Member
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Forgot to give you A/f ratios.....

jrgordonsenior is offline  
Old 10-04-2012, 12:08 AM
  #187  
Apex996
Addict
Rennlist Member
 
Apex996's Avatar
 
Join Date: Mar 2007
Location: fahre auf dem PittsbŘrgring
Posts: 586
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by logray View Post
Yes FVD goes to 76.4mm.

For sure I think this might help, if the stock 3.4L head ports can handle the extra volume.
Chew on this... The GT3 RSR has to breathe through a pair of 29mm restrictors. It makes 460 hp. Max. torque: 430 Nm at 7,250 rpm.

Apex996 is offline  
Old 10-15-2012, 11:47 PM
  #188  
HazardQ
New User
 
Join Date: Feb 2006
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by logray View Post
HOWEVER... (getting tired of howevers)

There is still a third related problem, once the car heats up, it still runs great, and idles great EXCEPT on a hot re-start it idles very poorly randomly, barely able to hold 680 RPM idle with no loads (stumbles a little as it dips lower) and then the ECU changes timing/adds fuel etc and gets the idle up and holds it steady and smooth for a long time, but will occasionally lose the 680 or 720 rpm and stumble again. In fact, it actually stalled on me at a stop light once. Once there is a load (A/C, fans, etc) it immediately smooths out again and can hold it indefinitely. No codes, of course, I'm dying for a code but the DME doesn't want to offer me any help.
Did you ever get this resolved? I've done the exact same thing that you did, with the exact same build, (threw a rod twice on the track, so two rebuilds) and I couldn't be happier!! What a machine it is now! (I actually did a bit more, single mass flywheel, Accusump, Oil crap, Tranny work, etc.) --- BTW, Love your head bolt idea, will do that next time I tear it apart.

What is driving me bonkers though is the idle. Since the car mostly plays on the track, it's not too bad of a problem, but I still have the original stock seats, and would like to drive it on the street more.
HazardQ is offline  
Old 10-16-2012, 12:28 PM
  #189  
logray
User
Thread Starter
 
logray's Avatar
 
Join Date: May 2010
Location: Nor Cal
Posts: 1,851
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by ApexComp View Post
Chew on this... The GT3 RSR has to breathe through a pair of 29mm restrictors. It makes 460 hp. Max. torque: 430 Nm at 7,250 rpm.
LOL!
logray is offline  
Old 10-16-2012, 12:32 PM
  #190  
logray
User
Thread Starter
 
logray's Avatar
 
Join Date: May 2010
Location: Nor Cal
Posts: 1,851
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by HazardQ View Post
Did you ever get this resolved? I've done the exact same thing that you did, with the exact same build, (threw a rod twice on the track, so two rebuilds) and I couldn't be happier!! What a machine it is now! (I actually did a bit more, single mass flywheel, Accusump, Oil crap, Tranny work, etc.) --- BTW, Love your head bolt idea, will do that next time I tear it apart.

What is driving me bonkers though is the idle. Since the car mostly plays on the track, it's not too bad of a problem, but I still have the original stock seats, and would like to drive it on the street more.
YES!!!! I did fix it!!!!

It was a combo problem. My IACV was toast, the open winding was only providing half the resistance (this was the biggest contributor). But other things that were contributing: I didn't upgrade the injectors when I upgraded the displacenent (leading to a computer induced rich condition, and even though I had swapped the injectors for larger ones the computer hadn't learned yet, it needed a reset and was still dumping too much fuel), my MAF and CPS were also marginal. ALSO, make sure you don't have any vacuum leaks. I didn't, but did a very thorough check.

Now it PUUUURRRRRSSS at idle, but I don't spend much time there (I like the other end of the tachometer better).

Oh, forgot to mention those 3.6L cans I bought from a RL member, one of them has a broken baffle inside and squeaks/rattles all over the place, so this winter it will be off to Dr Fister D for repairs.

Last edited by logray; 10-16-2012 at 12:49 PM.
logray is offline  
Old 07-30-2015, 12:20 PM
  #191  
AWDGuy
User
 
Join Date: Mar 2011
Posts: 1,769
Received 0 Likes on 0 Posts
Default

logray - hope you stillpost here

where did you get the torque specs/sequence for all the different bolts? manufacturer recommendations?
AWDGuy is offline  
Old 07-30-2015, 04:17 PM
  #192  
Hardback
Addict
Rennlist Member
 
Hardback's Avatar
 
Join Date: Jul 2008
Location: Miami, Fl.
Posts: 1,537
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by AWDGuy View Post
logray - hope you stillpost here

where did you get the torque specs/sequence for all the different bolts? manufacturer recommendations?
Havn't seen Logan here for a couple years. Try Renntech's forum.
Hardback is offline  

Thread Tools
Search this Thread
Quick Reply: Engine Rebuild Part 3 (the finale)


Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: